After optical fiber links are installed, some fiber links may not be in use (also known as “dark fibers”) in a network. Network operators who suffer lack of dark fibers may use various types of ring topology because an existing point-to-point topology may consume a large amount of fiber links. Typically, to set up an Ethernet ring, a switch router may be required, which is configured to support an Ethernet ring topology and provide failure protection features for the Ethernet ring network. However, switch routers are generally expensive to many network operators and thus replacing existing devices with the switch routers, such as box-type 2 plus 1 switches, to support an Ethernet ring type network in conventional networks may result in additional installation and maintenance costs, which may drive the costs of the network high. Hence, there is still a further need for improved and cost effective solutions to constructing a protected Ethernet ring network without incurring too much of additional costs and/or expenses in the existing networks.